"Bob La Londe" wrote in message
...
My Spindle Isn't Worn Out
Collets are Consumable

For the last month or so I started noticing alignment pin holes that
are spiral interpolated on one of my machines were a little loose.
Press fit pin holes were getting to where I could press them in with
my thumb. That's a bad thing. Those little high speed spindles have
a finite life and that one is a year old. I don't think it has the
6000hrs advertised for the bearings, but it might be getting close,
and honestly I usually get more than 6000hrs out of them Still to be
that loose I thought I'd be able to "feel" slop in them when the
spindle was cold first thing in the morning. No slop. Ok, how about
a runout test. Not much. Much less than 1/2 thou. Maybe 2-3 tenths.
Now to be fair I did a runout test with a dowel pin in a 1/4 inch
collet. Then I set up the indicator to measure travel backlash in
the table. Nope still just a hair under half thou, and that would
make smaller holes not larger. Finally I looked at the little 1/8
inch collet that was holding the 1/8 SE mill that was making the
oversize holes. Or rather I took a fresh new one out of the package
and cut a mold. Perfect. Everything is back to normal. I have to use
the arbor press to set pins again. That collet has outlasted one
spindle, has thousands of hours on this one, and has probably pushed
more than a couple small end mills to the breaking point. I guess I
can't complain about a very cheap Chinese ER16 collet. Collets are
consumable.

Did you measure the difference between the arbor press and thumb fit
interference?